abstract: Novel super acids offer the possibility of synthesizing hitherto unknown compounds.[1] Based on such Lewis and Brønsted acids, we have succeeded in synthesizing and characterizing so far unknown halonium ions, which are ideal alkylation reagents due to their high reactivity.[2,3] Furthermore it was shown, that e.g. chloronium ions can be stabilized by polychloride monoanions such as [Cl3]-.[4] Especially such polychloride anions offer new possibilities which are not only of academic interest.[5-8] The value of trichlorides for chlorine storage and chlorination reactions is only one aspect in this context. Particularly, the inexpensive ionic liquid [NEt3Me][Cl3] shows a similar and sometimes even advantageous reactivity compared to chlorine gas, while offering a superior safety profile. Furthermore, this chemistry shows also new applications in the direction of hydrochlorinations and beyond.